What is the best way to load on-page ads?

Question

Android

Good afternoon.
Tell me how best to implement the loading of multi-page advertising in the application. In which activity to load ads and from which to display it on the screen?
The scheme of the application where the display of advertising is of interest is as follows. The main activity-DialogFragment-for example, every time the fragment is closed for example 10, it is necessary to show an advertisement. In the fragment dialog, I already have a counter implemented through sharedpreferences.
Thank you.